1. Field of the Invention
This invention relates to fluid flow control systems and improved switching means for use therein.
2. Discussion of the Prior Art
Certain rotary type valves are known in the fluid flow control art such as U.S. Pat. Nos. 1,121,140 to Schoonmaker, 2,271,331 to Elliott, 2,567,428 to Greeley, 3,297,052 to Robinson, and 3,892,259 to McClocklin. Further, it is known to respectively connect lines to the vacuum and air pressure outputs of a pump and employ discrete switching means in each of the lines. However, the foregoing prior art system does not lend itself to rapid conversion from one mode of operation (that is, vacuum, for example) to another mode (that is, air pressure, for example), where the air pressure may or may not be continuously variable in magnitude.